This application is a 35 USC 371 of PCT/DK99/00691 filed Dec. 9, 1999.
The present invention relates to nail machines, and a roller ring and a fitting for such nail machine.
For instance, EP patent No 414 670 discloses state of the art nail machines for manufacturing elongate bodies with heads, such as nails, screws, tacks and other elongate bodies with heads, wherein the machine has a cutting station for cutting off individual pieces of wire that are subsequently received in a roller device that comprises a tool ring, said tool ring having an axis of rotation where about the tool ring can be caused to rotate; an outer and an inner surface that faces away from and towards, respectively, the axis of rotation of the tool ring, and a surface which is substantially perpendicular relative to the axis of rotation; and wherein the tool ring further comprises a plurality of holding jaws and means for positioning and securing the holding jaws at a mutual distance along the circumference of the tool ring; and wherein each holding jaw has a groove for receiving an elongate body longitudinally of said groove whereby the holding jaw is caused to serve as clamp jaw for securing and positioning the elongate body.
Hereby the holding jaw is able to contribute to securing the cut-off length of wire in order to enable that a head is rolled there onto, the holding jaw being configured such that the head is rolled out in a cavity configured on said holding tray.
The tool ring in these machines being configured for rotating about said axis of rotation, it is enabled that a continuous process is accomplished in which a plurality of holding jaws sequentially pass the point where the lengths of wire are cut off to enable that each cut-off length of wire is introduced into a holding jaw following which the holding jaw is displaced away from the cutting station and towards the roller station where the head is rolled onto the cut-off length of wire. Obviously, in order to achieve a high productivity for the machine such machines receive many lengths of wire per time unit, and this presupposes that the tool ring rotates at a relatively high rate of rotation. This means that it is extremely important that the individual holding jaws are very accurately situated along the circumference of the tool ring.
Besides, it is obvious that the holding jaws are secured effectively so as to prevent them from breaking loose and displacing in particular during the rolling process.
In the prior art machine this problem has been solved in that the tool ring is provided with a substantially cylindrical and radially inwardly oriented surface on the tool ring; and wherein the inwardly oriented surface is provided with a plurality of holding jaws and a corresponding number of wedge-shaped spacer blocks that are secured in firm abutment on the inwardly oriented surface by means of one or more machine bolts that are screwed into the tool ring. By this solution a holding jaw and a spacer block are thus alternatingly arranged until the entire above-mentioned, inwardly oriented surface is covered with holding jaws and spacer blocks that abut on each other. When the spacer blocks are subsequently clamped against the tool ring, the above-described wedge-shape of the spacer blocks causes the holding jaws to be wedged firmly between the spacer blocks, and by loosening and securing, respectively, the individual spacer blocks it is possible to regulate the mutual distance between the holding trays.
However, it is a problem in connection with this type of machine that the above-mentioned clamping process is very time-consuming, and that in practice it can only be performed to standard by an operator having considerable experience. Besides, provided a single block or holding jaw is loosened, crushed or deformed during use of the machine, this may entail that all the spacer blocks and holding jaws configured in the tool ring must subsequently be adjusted following attachment or securing of the loose or destroyed spacer block or holding tray.
Additionally, an alternative type of machine is known wherein the tool ring comprises a plurality of apertures in which a corresponding number of holding jaws can be configured that are each attached by means of a wedge-shape sleeve that extends around each holding tray, and wherein means are configured for displacing the wedges-shaped sleeve downwards into the apertures configured in the tool ring in such a manner that the holding jaw is wedged firmly into the aperture along with the wedges-shaped @sleeve. It is a problem of such machines, however, that the clamping of the holding jaws into the tool ring can entail deformations in the tool ring proper as a consequence of the wedging-in of the individual holding tray, which means that in this case, too, it is necessary to carry out a very accurate clamping of the individual holding tray, in order to ensure the best possible quality of the manufacture of the individual nails, screws, tacks and the like objects.
In the light of this, it is the object of the present invention to provide a machine whereby said drawbacks are fully or partially remedied.
In accordance with the invention, this is obtained in that the means for positioning and securing the holding jaws on the tool ring comprises a plurality of fittings that are removable from the tool ring, each of said fittings having means for receiving and securing at least one holding jaw in the fitting, and a support face that allows the fitting to abut on a support face that is complementary to the support face of the fitting, and which is configured on one of said surfaces on the tool ring; and means for clamping the fitting on the tool ring and wherein the fitting has at least one clamp surface which is opposite the support face; and wherein the means for clamping the fitting on the tool ring comprises a first element that abuts on the clamp face of the fitting and a second element that extends from the clamp face past the support face and engages with the tool ring.
Hereby it is indeed ensured that the forces necessary to ensure effective attachment of the individual jaws are, to the widest extent possible, received within the separate fitting itself, and that therefore these forces are not to a substantial extent transmitted as flexural forces to the tool ring.
Besides, the clamping itself and the mounting of the individual fittings make smaller requirements to the operator, since individual fittings and associated holding jaws can be replaced individually without thereby necessitating adjustment of the remaining holding trays, and since small variations in the clamping force have only a marginal bearing on the flexing of the tool ring.
The support face on the fitting and the complementary support face on the tool ring can, in a preferred embodiment of the invention, be configured such thatxe2x80x94following mounting of the fitting on the tool ringxe2x80x94the fitting extends completely outside the surface of the tool ring on which the fitting is mounted.
Additionally, the tool ring and the fitting can advantageously have complementary guide faces that ensure correct positioning of the fitting when being mounted on the tool ring.
In a preferred embodiment of a nail machine according to the invention, such machine comprises two tool rings arranged opposite each other in such a manner that their respective axes of rotation intersect at a blunt angle so as to cause two opposed holding jaws on the two tool rings to be pressed against each other along only a part of the periphery of the tool ring.
According to a particularly preferred embodiment of the invention whereby a particularly simple mounting of the individual fitting is obtained, the means for clamping the fittings onto the tool ring comprise a number of machine bolts; and wherein mounting apertures are provided at the complementary support faces on the tool ring, said mounting apertures being configured with a view to introduction of a machine bolt for securing the fitting onto the tool ring; and wherein the mounting aperture extends substantially perpendicular to the complementary support face on the tool ring. In this context the fitting advantageously comprises mounting apertures for insertion of the machine bolt, said mounting apertures extending through the fitting and substantially perpendicular to the support face of the fitting, and is arranged such that they correspond to the mounting apertures on the tool ring to allow a machine bolt to be inserted through each mounting aperture in the fitting, and into the corresponding mounting aperture on the tool ring, whereby the support face of the fitting is urged towards the corresponding complementary support face on the tool ring following mounting of the fitting thereon.
According to a further preferred embodiment of the invention, the fitting comprises at least two clamp faces that face each other, and means for shifting the two clamp faces towards each other in such a manner that a holding jaw can be clamped between the two clamp faces; and wherein the fitting is configured as a yoke with two legs and a spacer element that extends between the two legs; and wherein the clamp faces are situated at the end of each leg in such a manner that a tractive force occurs in the spacer element upon clamping of a holding jaw between the clamp faces.
In this context, the support face of the fitting can conveniently be located on the spacer element.
Besides, the clamp faces can conveniently be situated on that side of the spacer element which is opposite the support face of the fitting, whereby the spacer element willxe2x80x94following mounting of the fittingxe2x80x94extend between the holding jaw and the complementary support face.
According to a preferred embodiment, the fitting is configured for receiving only one holding tray, and at least one of the legs on the fitting extends across the spacer element at a distance there from; and the mounting apertures comprise a mounting aperture for each leg, said mounting aperture extending through the leg as well as the spacer element whereby the leg that extends a distance from the spacer element is pressed in a direction towards the spacer element by clamping of the fitting; and wherein the two clamp faces converge towards each other in a direction away from the spacer element, whereby the holding jaw is clamped firmly between the two clamp faces upon attachment of the fitting onto the tool ring.
According to an alternative embodiment the fitting can advantageously be configured for receiving two or more holding trays, and wherein the fitting comprises a number of loose clamp blocks that each has two oppositely oriented clamp faces, said loose clamp blocks being configured such that they can be positioned between the legs on the yoke in such a manner that, between the clamp blocks and between the clamp blocks and the legs on the yoke, a holding jaw can be received and attached.